1. Field of the Invention
The invention is related to the field of communications, and in particular, to backhaul for wireless communication systems
2. Description of the Prior Art
Wireless base stations communicate with users over wireless access links, such as Personal Communication Service (PCS) links, Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA) links, Microwave Multipoint Distribution Service (MMDS), and Global System for Mobile Communications (GSM) links. Typically, the base stations are mounted on elevated structures, such as building rooftops or towers. On the network side, the base stations communicate with a Mobile Switching Center. (MSC). The MSC exchanges user traffic between the base stations, and also between the base stations and local telephone systems, long distance telephone systems, and the Internet.
Time Division Multiplex (TDM) connections provide the communication capability between the base stations and the MSC. A dedicated TDM connection is often required between each base station and the MSC. These dedicated TDM connections are often DS1/DS3 connections that are leased from a local telephone company. Unfortunately, multiple leased TDM connections can be very expensive.
In addition, the dedicated nature of this bandwidth can be very inefficient. Different geographic areas have different busy hours, and thus, traffic patterns between base stations in these areas and the MSC also varies. When an area is busy, the TDM connections from that area to the MSC are also busy. Unfortunately, when an area is not busy, the expensive bandwidth on the dedicated TDM connections from that area to the MSC goes largely unused.
Wireless communication systems are available that provide 30 megabits of wireless bandwidth from a central point to multiple other points. These systems utilize point-to-multipoint radio equipment from Hughes or Cisco.
A circuit bonding device concatenates user communications for transfer over bonded circuits. At the receiving end, another circuit bonding device receives and de-concatenates the user communications. The circuits that are bonded together typically comprise unbundled network elements, such as twisted pairs, DS1 links, or DS3 links, that are obtained from Incumbent Local Exchange Carriers at wholesale rates pursuant to Federal rules. The circuit bonding devices may include Ethernet interfaces. One example of a conventional circuit bonding device is the equipment provided by Ceterus Networks.
Many metropolitan areas have communication rings. These rings transfer communications in Ethernet over Synchronous Optical Network (SONET) over Wave Division Multiplexing (WDM).
Unfortunately, point-to-multipoint radio, circuit bonding, and communication rings have not been effectively implemented to solve the cost and efficiency problems of wireless system backhaul.